So gas or Diesel engine won't matter as long as HP is same one will pull beside the other? Like the new 6.4 Hemi RAM will run with the trucks in the video? Cool
True statement with a few caveats.
#1. Gasoline engines are rated at sea-level so they make rated power at sea-level. Anything above that and they start losing power at about 3%/1000 feet. (Unless you have a EcoBoost.)
#2. Diesels have turbo's so they have next to no power loss at altitude.
So if you live or vacation near Denver this may be a consideration. If you live of vacation near LA, not so much.
As you may or may not know, they will pull, drive and sound completely different and the gas engine will burn about 30% more fuel. 30% is a bunch of fuel and can add up very fast if you tow a lot.
Most people report the diesel is a much more relaxing tow. I have towed with both and both are relaxing if I have enough power. Both are stressful if you don't have enough power.
Good luck with your new rig and have fun!